Manufacture of polishing-stones.



UNITED STATES PATENT OFFICE.

GUSTAV A. UNDEEN, F PROCTQR, VERMONT.

MANUFACTURE OF POLISHING-STONES.

1,099,831. No Drawing.

Specification of Letters Patent.

Application filed April 3,1912. Serial No. eaaasi.

. Patented June 9, 1914.

To all whom it may concern:

Be it known that I, GUSTAV A. UNDEEN, a citizen of the United States, residing at Proctor, in the county of Rutland and State of Vermont, have invented certain new and useful Improvements in the Manufacture of Polishing-Stones, of which the following is a specification.

This invention relates to the manufacture of polishing stones and has particular reference to a novelcomposition of matter for forming stones used to polish marble and to a novel process of producing the same.

The object of the invention is to produce a polishing stone, by the use of which a fine finish may be given to even the very poor grades of marble, and to so prepare the in- 3 gredients that a stone may be produced which will not scratch orin any way mar" the surface to be polished. Further objects are to produce a composition of the above character which Wlll 1mpart a superior finish to the work by the employment of simple and cheapingredients and to afford a novel process by which the ingredients are combined in a manner so as toobtain the most satisfactory results.

To these ends, the composition consists of emery powder, shellac, and rosin mixed in the proportions hereinafter recited, with or without the addition of a relatively small quantity of sulfur.

The process consists in melting a quantity of rosin and maintaining the heating thereof for a period of about two hours; in then mixing the rosin with a quantity of shellac, the fluid mixture being then strained and in adding emery powder to the fluid mass with the accompaniment of strong stirring, after which the mass may be run into molds and cast into ,the desired shape.

In effecting the present invention, I em powder No. 313, while the ordinary commercial grades of shellac and rosin will sufiice for the purpose. a

I will now proceed to describe'the manner in which the ingredients are combined for forming the improved polishing'stone.

A suitable quantity of rosin is melted and the heating is maintained for about two hours. While I have found that'thisprotracted heating of the rosin is necessary in order to obtain a polishing stonewhich will not be too hard and gives the desired waxy effect, I am unable to positively state whether there is any chemical change in'the rosin as a result'of the heating. In view, however, of the superior effect obtained by thus heatin the rosin, I am convinced that this step a ords a novel and valuable feature of the process. It is likely that certain substances, which in the commercial grades of rosin are found as impuritieswhich may have a deleterious effect on thefinal product, are volatilized during the heating and are thus eliminated. I then add the melted rosin to the proper quantity of shellacwhich may be either melted before its. addition to I the rosin or afterward. The molten mixture is then strained so as to eliminate solid impurities in the rosin and shellac which would {tend to scratch or otherwise mar the surface of the marble during'the polishing operation.- 'The heating of the mixture of ;shellac and rosin is then continued for a I short period after which the emery powder is addedto the mass, it being necessary strongly stir the mass during the addition of the powder and for several minutes there-' after. At any time after the emery powder has been added, but preferably after .the mixture has cooled somewhat, a sulfur may be added to the mixture, but this is not a necessary feature of the invention. The addition of the sulfur is advantageous,

however, ,in that it prevents the mass fromagglomerating, thus rendering the operation of. casting easier. After. the above operations, the mass is run into molds, where it is allowed to cool and assume the shape desiredxf' l I have found that the inclusion 'of the pinch of rosin prevents the mass from becoming too I hard when it is formed into stones, and by Y the treatment of the rosin above described,

that is, heating it for a considerable period,

the desired soft waxy effect is obtained in the polishing stones.

By experimentation I have demonstrated I tor a period approximating two hours, va-

rying, with' the grade of rosin employed, and have otherwise carried out'the process as above stated, with the result that a polishingstone has been produced capable of giving the finishing polish and starting the gloss on manble. On the other hand, I find that the mere melting of rosin without volatilization therefrom of the foreign substances, and'the making of the stone by the employment of rosin -with an abrasive compound,'which rosinvhas only been melted, results in'the'production 'ofa stone having I a tendency'to gum and adhere to the marble, producing smears and spots, WhlCll difliculties I have been able to overcome by the carrying out of the process as above set forth. While thereis no exact or definite period of time during which the rosin must be boiled, I find that approximately two hours is 'thej'eorrect time and the best-simple methqd'mf testing-whether the volatilization ,has been carried out to the required extent is by the introduction of a small stick into v the molten mass and the withdrawal of the stick .andcooling of the adhering rosin.

Preferably the cooling for this test is accomplished: by pouring cold water on the rosin coated stick. When cold, if the coat-.

H ing is hard'enough to'break easily when the stick is bent, theWolatilizing process has been carried out sufliciently, but if .whenj I I the stick is bent the coating ofrosin appears gummy and pliable, then the ess must becontinued' until the requlste extent of brittleness is attained. This is obviously only one simple test and other tests may be utilized as preferred, the essential feature of the process, so far a's'the treatment of the rosin isconcerned, residing in the factthat the rosin is heated to the volatilizing point and maintained at such point for a length of time giving it a consistency which will avoid the tendency on the part of the com leted stone to spot orotherwise glossed.

Having thus described the invention, what is claimed as new is: 1

1. A composition of matter for forming polishing stone, consisting of emery powder, shellac, and the product resulting from the heating of rosin to the volatilization point for about two hours.

2. A composition of matter ,for forming polishing stone, consisting of one part emery powder, three parts shellac, and two heating of rosin to the volatilization point for about two hours.

3. The process of manufacturing polishing stone comprising heating two parts of rosin to the volatilization pointfor about two hours, then melting about three parts shellac. and adding the same to the rosin, then straining said mixture to remove all spot producing plasticity and scratch producing matter, then adding one part emery and adding a relatively small quantity of sulfur,.and finally castin the mass: I In testimon whereof aflix my'signat'ure in presence 0 two witnessesl'. *1

L} GUSTAV AQUNDEEN. j, 'Witnesses:

H. C. ROBE,

.DUDLEY E. BURbIN E heating proc parts of the product resulting from the powder to the mass while stirring the same discolor t e marble being polished or g 

